Metal–insulator transition with an increase in the hydrogen content in amorphous chromium films
Abstract
It is found that an increase in the hydrogen content in amorphous chromium films deposited on a liquid-helium-cooled substrate leads to a considerable increase in the electrical resistivity and, in the limiting case, to a metal–insulator transition (MIT). The variation of the coordination structure of atomic arrangement and the temperature dependence of the resistivity are studied in the vicinity of the MIT. It is found that an increase in the atomic spacing and specific volume, which is the main reason behind the observed MIT. An analysis of the results shows that the investigated MIT is analogous to the Anderson transition observed earlier in expanding liquid mercury at high temperatures and associated with the formation of a “pseudogap” in the electron density of states. For the amorphous state of a solid, such a transition is observed for the first time.